Question

YOUR MASS SPECTROMETRY LAB HAS BEEN GIVEN A UNIQUE MISSION. YOU MUST BE ABLE TO DETECT SINGLE POINT MUTATIONS IN PROTEINS. YOUR LABORATORY HAS AVAILABLE ALL TYPES OF MASS SPECTROMETERS. WHICH TYPE OF MASS SPECTROMETER WOULD BEST MEET THE NEEDS OF THIS APPLICATION? EXPLAIN YOUR REASONING.

Answer 1

Solution

• Laser Desorption Mass Spectrometry is used for Point Mutation Detection.

• Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection.

• The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size.

• If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced.

• Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site.